This invention relates to integrated circuit chip packages and more particularly to integrated circuit chip packages adapted for packaging monolithic microwave integrated circuits (MMICs).
As is known in the art, packages are used to protect integrated circuits. Because of their relatively low cost, it is desirable to use plastic for the packages. While transfer molded plastic packages have been used for low frequency integrated circuit chip packages, such technique is not generally suitable for monolithic microwave integrated circuits (MMICs) because the plastic material on electrical wires used to connect the integrated circuit chip to a lead frame and over the surface of the MMIC itself has been found to adversely effect the performance of the integrated circuit. One package which has been suggested for MMICs is discussed in international patent application WO 94/17552 published Aug. 4, 1994. In such patent application, a lead frame having a baseplate for mounting a semiconductor chip is embedded on a surface of a platform of a plastic package.
In accordance with one feature of the invention, a package for an integrated circuit chip adapted to operate at microwave frequencies is provided. The package includes an electrically conductive lead frame having electrical leads extending outwardly from an inner region. A base section and plastic cover are adhesively bonded with the inner region of the lead-frame disposed therebetween. The base section and the cover are configured to encapsulate the integrated circuit chip within a cavity formed when the cover and the base section are bonded to provide the package.
With such a package, a low cost, electrically effective MMIC package is provided.
In one embodiment of the invention, the base section includes a dielectric member and in another embodiment the base section includes a dielectric member and a conductive member.
In accordance with another feature of the invention, a method for packaging an integrated circuit chip adapted to operate at microwave frequencies is provided. The method includes providing a lead frame having electrical leads extending outwardly from an inner region of the lead frame; affixing a base section to the lead frame with portions of the electrical leads extending outwardly from the base section and mounting the integrated circuit chip to the platform. Electrical wires are connected between the integrated circuit chip and the electrical leads. The base section and the cover are adhesively bonded with the integrated circuit chip and the electrical wires connected thereto disposed within a cavity formed by the affixed base section and cover.
With such method a relatively simple, low cost packaging technique is provided.
In accordance with another feature of the invention, a package for an integrated circuit chip adapted to operate at microwave frequencies is provided. The package includes an electrically conductive lead frame having electrical leads adapted for electrical connection to the integrated circuit. The base section includes an electrically conductive member and a dielectric member, such dielectric member having an aperture therein. The dielectric member aperture is disposed in registration with an inner region of the lead frame. An upper surface portion of the conductive member is adhesively bonded to a bottom surface portion of the dielectric member. Another upper surface portion of the conductive member is adapted for electrical connection to a bottom ground plane of the integrated circuit with such integrated circuit chip disposed in registration with the aperture. A plastic cover is adhesively affixed to upper portions of the lead frame and upper portions of the dielectric member, the plastic cover being configured to provide a cavity when the cover and the base section are affixed with the integrated circuit chip being disposed with such provided cavity and with a bottom surface portion of the conductive member being exposed exteriorly of the package to provide a ground plane connector for the bottom ground plane of the integrated circuit.
With such package, the bottom ground plane of the integrated circuit chip may be easily connected to the ground plane provided by the conductive member.
In accordance with another feature of the invention, a method is provided for packaging an integrated circuit chip adapted to operate at microwave frequencies. The method includes the steps of: providing a lead frame having electrical leads extending outwardly from an inner region of the lead frame; providing a base section having a conductive member and a dielectric member, the dielectric member having an aperture; connecting electrical wires between the integrated circuit chip and the electrical leads and a bottom ground plane of the integrated circuit chip to the electrically conductive member with the integrated circuit chip being in registration with the aperture; and, adhesively affixing the base section to a plastic cover to provide a package for the integrated circuit chip and the electrical wires connected thereto within a cavity provided by adhesively affixed base section and dielectric cover with a portion of the electrically conductive member being exposed exteriorly of the package.
With such method the bottom surface of the integrated circuit chip may be easily grounded externally using a surface external to the package.
In accordance with still another feature of the invention, a package an integrated circuit chip adapted to operate at microwave frequencies is provided. The package includes: (a) a lead frame having electrical leads extending outwardly from an inner region of the lead frame; (b) a base section comprising: a dielectric member having an aperture and; an electrically conductive member having an upper surface adapted for electrical connection to a bottom ground plane of the integrated circuit chip when the integrated circuit chip is in registration with the aperture; and (c) a dielectric cover, such cover being configured to provide a cavity for the integrated circuit chip when the cover and the base section are affixed and to expose a bottom portion of the conductive member exteriorly of the package.